Novias Camouflage 3L Hydration Backpack Bladder Water Bag for Climbing Running Hiking Cycling Survival Outdoor Backpack Christmas Gift Constructed by waterproof 600D high density Nylon material, this Hydration Backpack came with a free gift: a fitness belt Size 7.5 x 17.7, capacity: 3 Liters, super light weight 0.88lb Two layers cargo design, one for hydration bladder, and the other for extra carrying purpose Adjustable shoulder strap and chest belt, suitable for heavy carrying Equipped with a tube with a bite valve to drink, so you don't need to hold it to drink